Commit | Line | Data |
---|---|---|
2691221a MD |
1 | /* |
2 | * lttng-ust-comm.c | |
3 | * | |
4 | * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca> | |
5 | * Copyright (C) 2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
6 | * | |
7 | * This library is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; only | |
10 | * version 2.1 of the License. | |
11 | * | |
12 | * This library is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with this library; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
80e2814b | 22 | #define _LGPL_SOURCE |
2691221a MD |
23 | #include <sys/types.h> |
24 | #include <sys/socket.h> | |
7fc90dca MD |
25 | #include <sys/mman.h> |
26 | #include <sys/stat.h> | |
58d4b2a2 MD |
27 | #include <sys/types.h> |
28 | #include <sys/wait.h> | |
7fc90dca | 29 | #include <fcntl.h> |
2691221a MD |
30 | #include <unistd.h> |
31 | #include <errno.h> | |
d9e99d10 | 32 | #include <pthread.h> |
11ff9c7d MD |
33 | #include <semaphore.h> |
34 | #include <time.h> | |
1ea11eab | 35 | #include <assert.h> |
e822f505 | 36 | #include <signal.h> |
95259bd0 | 37 | #include <urcu/uatomic.h> |
80e2814b | 38 | #include <urcu/futex.h> |
c117fb1b | 39 | #include <urcu/compiler.h> |
1ea11eab | 40 | |
4318ae1b | 41 | #include <lttng/ust-events.h> |
4318ae1b | 42 | #include <lttng/ust-abi.h> |
4318ae1b | 43 | #include <lttng/ust.h> |
44c72f10 MD |
44 | #include <ust-comm.h> |
45 | #include <usterr-signal-safe.h> | |
46 | #include "tracepoint-internal.h" | |
b751f722 | 47 | #include "ltt-tracer-core.h" |
08114193 | 48 | #include "compat.h" |
edaa1431 MD |
49 | |
50 | /* | |
51 | * Has lttng ust comm constructor been called ? | |
52 | */ | |
53 | static int initialized; | |
54 | ||
1ea11eab | 55 | /* |
17dfb34b MD |
56 | * The ust_lock/ust_unlock lock is used as a communication thread mutex. |
57 | * Held when handling a command, also held by fork() to deal with | |
58 | * removal of threads, and by exit path. | |
1ea11eab | 59 | */ |
1ea11eab MD |
60 | |
61 | /* Should the ust comm thread quit ? */ | |
62 | static int lttng_ust_comm_should_quit; | |
63 | ||
11ff9c7d MD |
64 | /* |
65 | * Wait for either of these before continuing to the main | |
66 | * program: | |
67 | * - the register_done message from sessiond daemon | |
68 | * (will let the sessiond daemon enable sessions before main | |
69 | * starts.) | |
70 | * - sessiond daemon is not reachable. | |
71 | * - timeout (ensuring applications are resilient to session | |
72 | * daemon problems). | |
73 | */ | |
74 | static sem_t constructor_wait; | |
950aab0c MD |
75 | /* |
76 | * Doing this for both the global and local sessiond. | |
77 | */ | |
95259bd0 | 78 | static int sem_count = { 2 }; |
11ff9c7d | 79 | |
1ea11eab MD |
80 | /* |
81 | * Info about socket and associated listener thread. | |
82 | */ | |
83 | struct sock_info { | |
11ff9c7d | 84 | const char *name; |
1ea11eab | 85 | pthread_t ust_listener; /* listener thread */ |
46050b1a | 86 | int root_handle; |
8d20bf54 MD |
87 | int constructor_sem_posted; |
88 | int allowed; | |
44e073f5 | 89 | int global; |
7fc90dca MD |
90 | |
91 | char sock_path[PATH_MAX]; | |
92 | int socket; | |
93 | ||
94 | char wait_shm_path[PATH_MAX]; | |
95 | char *wait_shm_mmap; | |
1ea11eab | 96 | }; |
2691221a MD |
97 | |
98 | /* Socket from app (connect) to session daemon (listen) for communication */ | |
1ea11eab | 99 | struct sock_info global_apps = { |
11ff9c7d | 100 | .name = "global", |
44e073f5 | 101 | .global = 1, |
7fc90dca | 102 | |
46050b1a | 103 | .root_handle = -1, |
8d20bf54 | 104 | .allowed = 1, |
7fc90dca MD |
105 | |
106 | .sock_path = DEFAULT_GLOBAL_APPS_UNIX_SOCK, | |
107 | .socket = -1, | |
108 | ||
109 | .wait_shm_path = DEFAULT_GLOBAL_APPS_WAIT_SHM_PATH, | |
1ea11eab | 110 | }; |
2691221a MD |
111 | |
112 | /* TODO: allow global_apps_sock_path override */ | |
113 | ||
1ea11eab | 114 | struct sock_info local_apps = { |
11ff9c7d | 115 | .name = "local", |
44e073f5 | 116 | .global = 0, |
46050b1a | 117 | .root_handle = -1, |
8d20bf54 | 118 | .allowed = 0, /* Check setuid bit first */ |
7fc90dca MD |
119 | |
120 | .socket = -1, | |
1ea11eab | 121 | }; |
2691221a | 122 | |
37ed587a MD |
123 | static int wait_poll_fallback; |
124 | ||
edaa1431 MD |
125 | extern void ltt_ring_buffer_client_overwrite_init(void); |
126 | extern void ltt_ring_buffer_client_discard_init(void); | |
127 | extern void ltt_ring_buffer_metadata_client_init(void); | |
128 | extern void ltt_ring_buffer_client_overwrite_exit(void); | |
129 | extern void ltt_ring_buffer_client_discard_exit(void); | |
130 | extern void ltt_ring_buffer_metadata_client_exit(void); | |
131 | ||
2691221a | 132 | static |
8d20bf54 | 133 | int setup_local_apps(void) |
2691221a MD |
134 | { |
135 | const char *home_dir; | |
7fc90dca | 136 | uid_t uid; |
2691221a | 137 | |
7fc90dca | 138 | uid = getuid(); |
8d20bf54 MD |
139 | /* |
140 | * Disallow per-user tracing for setuid binaries. | |
141 | */ | |
7fc90dca | 142 | if (uid != geteuid()) { |
8d20bf54 | 143 | local_apps.allowed = 0; |
d0a1ae63 | 144 | return 0; |
8d20bf54 MD |
145 | } else { |
146 | local_apps.allowed = 1; | |
147 | } | |
2691221a MD |
148 | home_dir = (const char *) getenv("HOME"); |
149 | if (!home_dir) | |
150 | return -ENOENT; | |
1ea11eab | 151 | snprintf(local_apps.sock_path, PATH_MAX, |
2691221a | 152 | DEFAULT_HOME_APPS_UNIX_SOCK, home_dir); |
7fc90dca MD |
153 | snprintf(local_apps.wait_shm_path, PATH_MAX, |
154 | DEFAULT_HOME_APPS_WAIT_SHM_PATH, uid); | |
2691221a MD |
155 | return 0; |
156 | } | |
157 | ||
158 | static | |
159 | int register_app_to_sessiond(int socket) | |
160 | { | |
161 | ssize_t ret; | |
162 | struct { | |
e44418f3 MD |
163 | uint32_t major; |
164 | uint32_t minor; | |
2691221a | 165 | pid_t pid; |
5c33bde8 | 166 | pid_t ppid; |
2691221a | 167 | uid_t uid; |
83610856 | 168 | gid_t gid; |
c117fb1b | 169 | uint32_t bits_per_long; |
2629549e | 170 | char name[16]; /* process name */ |
2691221a MD |
171 | } reg_msg; |
172 | ||
e44418f3 MD |
173 | reg_msg.major = LTTNG_UST_COMM_VERSION_MAJOR; |
174 | reg_msg.minor = LTTNG_UST_COMM_VERSION_MINOR; | |
2691221a | 175 | reg_msg.pid = getpid(); |
5c33bde8 | 176 | reg_msg.ppid = getppid(); |
2691221a | 177 | reg_msg.uid = getuid(); |
83610856 | 178 | reg_msg.gid = getgid(); |
c117fb1b | 179 | reg_msg.bits_per_long = CAA_BITS_PER_LONG; |
08114193 | 180 | lttng_ust_getprocname(reg_msg.name); |
2691221a | 181 | |
57773204 | 182 | ret = ustcomm_send_unix_sock(socket, ®_msg, sizeof(reg_msg)); |
2691221a MD |
183 | if (ret >= 0 && ret != sizeof(reg_msg)) |
184 | return -EIO; | |
185 | return ret; | |
186 | } | |
187 | ||
d9e99d10 | 188 | static |
57773204 | 189 | int send_reply(int sock, struct ustcomm_ust_reply *lur) |
d9e99d10 | 190 | { |
9eb62b9c | 191 | ssize_t len; |
d3a492d1 | 192 | |
57773204 | 193 | len = ustcomm_send_unix_sock(sock, lur, sizeof(*lur)); |
d3a492d1 | 194 | switch (len) { |
a4be8962 | 195 | case sizeof(*lur): |
d3a492d1 MD |
196 | DBG("message successfully sent"); |
197 | return 0; | |
198 | case -1: | |
199 | if (errno == ECONNRESET) { | |
200 | printf("remote end closed connection\n"); | |
201 | return 0; | |
202 | } | |
203 | return -1; | |
204 | default: | |
205 | printf("incorrect message size: %zd\n", len); | |
206 | return -1; | |
207 | } | |
208 | } | |
209 | ||
210 | static | |
edaa1431 | 211 | int handle_register_done(struct sock_info *sock_info) |
11ff9c7d MD |
212 | { |
213 | int ret; | |
214 | ||
edaa1431 MD |
215 | if (sock_info->constructor_sem_posted) |
216 | return 0; | |
217 | sock_info->constructor_sem_posted = 1; | |
56cd7e2f MD |
218 | if (uatomic_read(&sem_count) <= 0) { |
219 | return 0; | |
220 | } | |
95259bd0 MD |
221 | ret = uatomic_add_return(&sem_count, -1); |
222 | if (ret == 0) { | |
223 | ret = sem_post(&constructor_wait); | |
224 | assert(!ret); | |
225 | } | |
11ff9c7d MD |
226 | return 0; |
227 | } | |
228 | ||
229 | static | |
230 | int handle_message(struct sock_info *sock_info, | |
57773204 | 231 | int sock, struct ustcomm_ust_msg *lum) |
d3a492d1 | 232 | { |
1ea11eab | 233 | int ret = 0; |
b61ce3b2 | 234 | const struct lttng_ust_objd_ops *ops; |
57773204 | 235 | struct ustcomm_ust_reply lur; |
193183fb | 236 | int shm_fd, wait_fd; |
ef9ff354 | 237 | union ust_args args; |
1ea11eab | 238 | |
17dfb34b | 239 | ust_lock(); |
1ea11eab | 240 | |
46050b1a MD |
241 | memset(&lur, 0, sizeof(lur)); |
242 | ||
1ea11eab | 243 | if (lttng_ust_comm_should_quit) { |
46050b1a | 244 | ret = -EPERM; |
1ea11eab MD |
245 | goto end; |
246 | } | |
9eb62b9c | 247 | |
46050b1a MD |
248 | ops = objd_ops(lum->handle); |
249 | if (!ops) { | |
250 | ret = -ENOENT; | |
251 | goto end; | |
1ea11eab | 252 | } |
46050b1a MD |
253 | |
254 | switch (lum->cmd) { | |
11ff9c7d MD |
255 | case LTTNG_UST_REGISTER_DONE: |
256 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
edaa1431 | 257 | ret = handle_register_done(sock_info); |
11ff9c7d MD |
258 | else |
259 | ret = -EINVAL; | |
260 | break; | |
46050b1a MD |
261 | case LTTNG_UST_RELEASE: |
262 | if (lum->handle == LTTNG_UST_ROOT_HANDLE) | |
263 | ret = -EPERM; | |
264 | else | |
d4419b81 | 265 | ret = lttng_ust_objd_unref(lum->handle); |
d9e99d10 MD |
266 | break; |
267 | default: | |
46050b1a MD |
268 | if (ops->cmd) |
269 | ret = ops->cmd(lum->handle, lum->cmd, | |
ef9ff354 MD |
270 | (unsigned long) &lum->u, |
271 | &args); | |
46050b1a MD |
272 | else |
273 | ret = -ENOSYS; | |
274 | break; | |
d9e99d10 | 275 | } |
46050b1a | 276 | |
1ea11eab | 277 | end: |
46050b1a MD |
278 | lur.handle = lum->handle; |
279 | lur.cmd = lum->cmd; | |
280 | lur.ret_val = ret; | |
281 | if (ret >= 0) { | |
57773204 | 282 | lur.ret_code = USTCOMM_OK; |
46050b1a | 283 | } else { |
57773204 | 284 | //lur.ret_code = USTCOMM_SESSION_FAIL; |
193183fb | 285 | lur.ret_code = ret; |
46050b1a | 286 | } |
193183fb MD |
287 | switch (lum->cmd) { |
288 | case LTTNG_UST_STREAM: | |
381c0f1e MD |
289 | /* |
290 | * Special-case reply to send stream info. | |
291 | * Use lum.u output. | |
292 | */ | |
ef9ff354 MD |
293 | lur.u.stream.memory_map_size = *args.stream.memory_map_size; |
294 | shm_fd = *args.stream.shm_fd; | |
295 | wait_fd = *args.stream.wait_fd; | |
193183fb | 296 | break; |
824f40b8 | 297 | case LTTNG_UST_METADATA: |
193183fb | 298 | case LTTNG_UST_CHANNEL: |
ef9ff354 MD |
299 | lur.u.channel.memory_map_size = *args.channel.memory_map_size; |
300 | shm_fd = *args.channel.shm_fd; | |
301 | wait_fd = *args.channel.wait_fd; | |
193183fb | 302 | break; |
23c8854a | 303 | case LTTNG_UST_TRACER_VERSION: |
57773204 MD |
304 | lur.u.version = lum->u.version; |
305 | break; | |
b115631f | 306 | case LTTNG_UST_TRACEPOINT_LIST_GET: |
cbef6901 | 307 | memcpy(&lur.u.tracepoint, &lum->u.tracepoint, sizeof(lur.u.tracepoint)); |
b115631f | 308 | break; |
381c0f1e | 309 | } |
46050b1a | 310 | ret = send_reply(sock, &lur); |
193183fb MD |
311 | if (ret < 0) { |
312 | perror("error sending reply"); | |
313 | goto error; | |
314 | } | |
46050b1a | 315 | |
824f40b8 MD |
316 | if ((lum->cmd == LTTNG_UST_STREAM |
317 | || lum->cmd == LTTNG_UST_CHANNEL | |
318 | || lum->cmd == LTTNG_UST_METADATA) | |
57773204 | 319 | && lur.ret_code == USTCOMM_OK) { |
381c0f1e | 320 | /* we also need to send the file descriptors. */ |
57773204 | 321 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 322 | &shm_fd, &shm_fd, |
381c0f1e MD |
323 | 1, sizeof(int)); |
324 | if (ret < 0) { | |
325 | perror("send shm_fd"); | |
326 | goto error; | |
327 | } | |
57773204 | 328 | ret = ustcomm_send_fds_unix_sock(sock, |
193183fb | 329 | &wait_fd, &wait_fd, |
381c0f1e MD |
330 | 1, sizeof(int)); |
331 | if (ret < 0) { | |
332 | perror("send wait_fd"); | |
333 | goto error; | |
334 | } | |
335 | } | |
ef9ff354 MD |
336 | /* |
337 | * We still have the memory map reference, and the fds have been | |
3ad5f707 MD |
338 | * sent to the sessiond. We can therefore close those fds. Note |
339 | * that we keep the write side of the wait_fd open, but close | |
340 | * the read side. | |
ef9ff354 MD |
341 | */ |
342 | if (lur.ret_code == USTCOMM_OK) { | |
343 | switch (lum->cmd) { | |
344 | case LTTNG_UST_STREAM: | |
345 | if (shm_fd >= 0) { | |
346 | ret = close(shm_fd); | |
347 | if (ret) { | |
348 | PERROR("Error closing stream shm_fd"); | |
349 | } | |
350 | *args.stream.shm_fd = -1; | |
351 | } | |
352 | if (wait_fd >= 0) { | |
353 | ret = close(wait_fd); | |
354 | if (ret) { | |
355 | PERROR("Error closing stream wait_fd"); | |
356 | } | |
357 | *args.stream.wait_fd = -1; | |
358 | } | |
359 | break; | |
360 | case LTTNG_UST_METADATA: | |
361 | case LTTNG_UST_CHANNEL: | |
362 | if (shm_fd >= 0) { | |
363 | ret = close(shm_fd); | |
364 | if (ret) { | |
365 | PERROR("Error closing channel shm_fd"); | |
366 | } | |
367 | *args.channel.shm_fd = -1; | |
368 | } | |
369 | if (wait_fd >= 0) { | |
370 | ret = close(wait_fd); | |
371 | if (ret) { | |
372 | PERROR("Error closing channel wait_fd"); | |
373 | } | |
374 | *args.channel.wait_fd = -1; | |
375 | } | |
376 | break; | |
377 | } | |
378 | } | |
379 | ||
381c0f1e | 380 | error: |
17dfb34b | 381 | ust_unlock(); |
1ea11eab | 382 | return ret; |
d9e99d10 MD |
383 | } |
384 | ||
46050b1a | 385 | static |
efe0de09 | 386 | void cleanup_sock_info(struct sock_info *sock_info, int exiting) |
46050b1a MD |
387 | { |
388 | int ret; | |
389 | ||
390 | if (sock_info->socket != -1) { | |
391 | ret = close(sock_info->socket); | |
392 | if (ret) { | |
7fc90dca | 393 | ERR("Error closing apps socket"); |
46050b1a MD |
394 | } |
395 | sock_info->socket = -1; | |
396 | } | |
397 | if (sock_info->root_handle != -1) { | |
d4419b81 | 398 | ret = lttng_ust_objd_unref(sock_info->root_handle); |
46050b1a MD |
399 | if (ret) { |
400 | ERR("Error unref root handle"); | |
401 | } | |
402 | sock_info->root_handle = -1; | |
403 | } | |
318dfea9 | 404 | sock_info->constructor_sem_posted = 0; |
efe0de09 MD |
405 | /* |
406 | * wait_shm_mmap is used by listener threads outside of the | |
407 | * ust lock, so we cannot tear it down ourselves, because we | |
408 | * cannot join on these threads. Leave this task to the OS | |
409 | * process exit. | |
410 | */ | |
411 | if (!exiting && sock_info->wait_shm_mmap) { | |
7fc90dca MD |
412 | ret = munmap(sock_info->wait_shm_mmap, sysconf(_SC_PAGE_SIZE)); |
413 | if (ret) { | |
414 | ERR("Error unmapping wait shm"); | |
415 | } | |
416 | sock_info->wait_shm_mmap = NULL; | |
417 | } | |
418 | } | |
419 | ||
58d4b2a2 | 420 | /* |
33bbeb90 MD |
421 | * Using fork to set umask in the child process (not multi-thread safe). |
422 | * We deal with the shm_open vs ftruncate race (happening when the | |
423 | * sessiond owns the shm and does not let everybody modify it, to ensure | |
424 | * safety against shm_unlink) by simply letting the mmap fail and | |
425 | * retrying after a few seconds. | |
426 | * For global shm, everybody has rw access to it until the sessiond | |
427 | * starts. | |
58d4b2a2 | 428 | */ |
7fc90dca | 429 | static |
58d4b2a2 | 430 | int get_wait_shm(struct sock_info *sock_info, size_t mmap_size) |
7fc90dca | 431 | { |
7fc90dca | 432 | int wait_shm_fd, ret; |
58d4b2a2 | 433 | pid_t pid; |
44e073f5 | 434 | |
58d4b2a2 | 435 | /* |
33bbeb90 | 436 | * Try to open read-only. |
58d4b2a2 | 437 | */ |
33bbeb90 | 438 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
439 | if (wait_shm_fd >= 0) { |
440 | goto end; | |
441 | } else if (wait_shm_fd < 0 && errno != ENOENT) { | |
442 | /* | |
33bbeb90 MD |
443 | * Real-only open did not work, and it's not because the |
444 | * entry was not present. It's a failure that prohibits | |
445 | * using shm. | |
58d4b2a2 | 446 | */ |
7fc90dca | 447 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
58d4b2a2 | 448 | goto end; |
7fc90dca MD |
449 | } |
450 | /* | |
58d4b2a2 MD |
451 | * If the open failed because the file did not exist, try |
452 | * creating it ourself. | |
7fc90dca | 453 | */ |
58d4b2a2 MD |
454 | pid = fork(); |
455 | if (pid > 0) { | |
456 | int status; | |
457 | ||
458 | /* | |
459 | * Parent: wait for child to return, in which case the | |
460 | * shared memory map will have been created. | |
461 | */ | |
462 | pid = wait(&status); | |
b7d3cb32 | 463 | if (pid < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { |
58d4b2a2 MD |
464 | wait_shm_fd = -1; |
465 | goto end; | |
7fc90dca | 466 | } |
58d4b2a2 MD |
467 | /* |
468 | * Try to open read-only again after creation. | |
469 | */ | |
33bbeb90 | 470 | wait_shm_fd = shm_open(sock_info->wait_shm_path, O_RDONLY, 0); |
58d4b2a2 MD |
471 | if (wait_shm_fd < 0) { |
472 | /* | |
473 | * Real-only open did not work. It's a failure | |
474 | * that prohibits using shm. | |
475 | */ | |
476 | ERR("Error opening shm %s", sock_info->wait_shm_path); | |
477 | goto end; | |
478 | } | |
479 | goto end; | |
480 | } else if (pid == 0) { | |
481 | int create_mode; | |
482 | ||
483 | /* Child */ | |
33bbeb90 | 484 | create_mode = S_IRUSR | S_IWUSR | S_IRGRP; |
58d4b2a2 | 485 | if (sock_info->global) |
33bbeb90 | 486 | create_mode |= S_IROTH | S_IWGRP | S_IWOTH; |
58d4b2a2 MD |
487 | /* |
488 | * We're alone in a child process, so we can modify the | |
489 | * process-wide umask. | |
490 | */ | |
33bbeb90 | 491 | umask(~create_mode); |
58d4b2a2 | 492 | /* |
33bbeb90 MD |
493 | * Try creating shm (or get rw access). |
494 | * We don't do an exclusive open, because we allow other | |
495 | * processes to create+ftruncate it concurrently. | |
58d4b2a2 MD |
496 | */ |
497 | wait_shm_fd = shm_open(sock_info->wait_shm_path, | |
498 | O_RDWR | O_CREAT, create_mode); | |
499 | if (wait_shm_fd >= 0) { | |
500 | ret = ftruncate(wait_shm_fd, mmap_size); | |
501 | if (ret) { | |
502 | PERROR("ftruncate"); | |
503 | exit(EXIT_FAILURE); | |
504 | } | |
58d4b2a2 MD |
505 | exit(EXIT_SUCCESS); |
506 | } | |
33bbeb90 MD |
507 | /* |
508 | * For local shm, we need to have rw access to accept | |
509 | * opening it: this means the local sessiond will be | |
510 | * able to wake us up. For global shm, we open it even | |
511 | * if rw access is not granted, because the root.root | |
512 | * sessiond will be able to override all rights and wake | |
513 | * us up. | |
514 | */ | |
515 | if (!sock_info->global && errno != EACCES) { | |
58d4b2a2 MD |
516 | ERR("Error opening shm %s", sock_info->wait_shm_path); |
517 | exit(EXIT_FAILURE); | |
518 | } | |
519 | /* | |
33bbeb90 MD |
520 | * The shm exists, but we cannot open it RW. Report |
521 | * success. | |
58d4b2a2 MD |
522 | */ |
523 | exit(EXIT_SUCCESS); | |
524 | } else { | |
525 | return -1; | |
7fc90dca | 526 | } |
58d4b2a2 | 527 | end: |
33bbeb90 MD |
528 | if (wait_shm_fd >= 0 && !sock_info->global) { |
529 | struct stat statbuf; | |
530 | ||
531 | /* | |
532 | * Ensure that our user is the owner of the shm file for | |
533 | * local shm. If we do not own the file, it means our | |
534 | * sessiond will not have access to wake us up (there is | |
535 | * probably a rogue process trying to fake our | |
536 | * sessiond). Fallback to polling method in this case. | |
537 | */ | |
538 | ret = fstat(wait_shm_fd, &statbuf); | |
539 | if (ret) { | |
540 | PERROR("fstat"); | |
541 | goto error_close; | |
542 | } | |
543 | if (statbuf.st_uid != getuid()) | |
544 | goto error_close; | |
545 | } | |
58d4b2a2 | 546 | return wait_shm_fd; |
33bbeb90 MD |
547 | |
548 | error_close: | |
549 | ret = close(wait_shm_fd); | |
550 | if (ret) { | |
551 | PERROR("Error closing fd"); | |
552 | } | |
553 | return -1; | |
58d4b2a2 MD |
554 | } |
555 | ||
556 | static | |
557 | char *get_map_shm(struct sock_info *sock_info) | |
558 | { | |
559 | size_t mmap_size = sysconf(_SC_PAGE_SIZE); | |
560 | int wait_shm_fd, ret; | |
561 | char *wait_shm_mmap; | |
562 | ||
563 | wait_shm_fd = get_wait_shm(sock_info, mmap_size); | |
564 | if (wait_shm_fd < 0) { | |
565 | goto error; | |
44e073f5 | 566 | } |
7fc90dca MD |
567 | wait_shm_mmap = mmap(NULL, mmap_size, PROT_READ, |
568 | MAP_SHARED, wait_shm_fd, 0); | |
7fc90dca MD |
569 | /* close shm fd immediately after taking the mmap reference */ |
570 | ret = close(wait_shm_fd); | |
571 | if (ret) { | |
33bbeb90 MD |
572 | PERROR("Error closing fd"); |
573 | } | |
574 | if (wait_shm_mmap == MAP_FAILED) { | |
575 | DBG("mmap error (can be caused by race with sessiond). Fallback to poll mode."); | |
576 | goto error; | |
7fc90dca MD |
577 | } |
578 | return wait_shm_mmap; | |
579 | ||
580 | error: | |
581 | return NULL; | |
582 | } | |
583 | ||
584 | static | |
585 | void wait_for_sessiond(struct sock_info *sock_info) | |
586 | { | |
efe0de09 | 587 | int ret; |
80e2814b | 588 | |
7fc90dca MD |
589 | ust_lock(); |
590 | if (lttng_ust_comm_should_quit) { | |
591 | goto quit; | |
592 | } | |
37ed587a MD |
593 | if (wait_poll_fallback) { |
594 | goto error; | |
595 | } | |
7fc90dca MD |
596 | if (!sock_info->wait_shm_mmap) { |
597 | sock_info->wait_shm_mmap = get_map_shm(sock_info); | |
598 | if (!sock_info->wait_shm_mmap) | |
599 | goto error; | |
600 | } | |
601 | ust_unlock(); | |
602 | ||
603 | DBG("Waiting for %s apps sessiond", sock_info->name); | |
80e2814b MD |
604 | /* Wait for futex wakeup */ |
605 | if (uatomic_read((int32_t *) sock_info->wait_shm_mmap) == 0) { | |
606 | ret = futex_async((int32_t *) sock_info->wait_shm_mmap, | |
607 | FUTEX_WAIT, 0, NULL, NULL, 0); | |
80e2814b | 608 | if (ret < 0) { |
37ed587a MD |
609 | if (errno == EFAULT) { |
610 | wait_poll_fallback = 1; | |
a8b870ad | 611 | DBG( |
37ed587a MD |
612 | "Linux kernels 2.6.33 to 3.0 (with the exception of stable versions) " |
613 | "do not support FUTEX_WAKE on read-only memory mappings correctly. " | |
614 | "Please upgrade your kernel " | |
615 | "(fix is commit 9ea71503a8ed9184d2d0b8ccc4d269d05f7940ae in Linux kernel " | |
616 | "mainline). LTTng-UST will use polling mode fallback."); | |
cd27263b MD |
617 | if (ust_debug()) |
618 | PERROR("futex"); | |
37ed587a | 619 | } |
80e2814b MD |
620 | } |
621 | } | |
7fc90dca MD |
622 | return; |
623 | ||
624 | quit: | |
625 | ust_unlock(); | |
626 | return; | |
627 | ||
628 | error: | |
629 | ust_unlock(); | |
7fc90dca | 630 | return; |
46050b1a MD |
631 | } |
632 | ||
1ea11eab MD |
633 | /* |
634 | * This thread does not allocate any resource, except within | |
635 | * handle_message, within mutex protection. This mutex protects against | |
636 | * fork and exit. | |
637 | * The other moment it allocates resources is at socket connexion, which | |
638 | * is also protected by the mutex. | |
639 | */ | |
d9e99d10 MD |
640 | static |
641 | void *ust_listener_thread(void *arg) | |
642 | { | |
1ea11eab | 643 | struct sock_info *sock_info = arg; |
c0eedf81 | 644 | int sock, ret, prev_connect_failed = 0, has_waited = 0; |
d9e99d10 | 645 | |
9eb62b9c MD |
646 | /* Restart trying to connect to the session daemon */ |
647 | restart: | |
c0eedf81 MD |
648 | if (prev_connect_failed) { |
649 | /* Wait for sessiond availability with pipe */ | |
650 | wait_for_sessiond(sock_info); | |
651 | if (has_waited) { | |
652 | has_waited = 0; | |
653 | /* | |
654 | * Sleep for 5 seconds before retrying after a | |
655 | * sequence of failure / wait / failure. This | |
656 | * deals with a killed or broken session daemon. | |
657 | */ | |
658 | sleep(5); | |
659 | } | |
660 | has_waited = 1; | |
661 | prev_connect_failed = 0; | |
662 | } | |
17dfb34b | 663 | ust_lock(); |
1ea11eab MD |
664 | |
665 | if (lttng_ust_comm_should_quit) { | |
17dfb34b | 666 | ust_unlock(); |
1ea11eab MD |
667 | goto quit; |
668 | } | |
9eb62b9c | 669 | |
1ea11eab MD |
670 | if (sock_info->socket != -1) { |
671 | ret = close(sock_info->socket); | |
672 | if (ret) { | |
11ff9c7d | 673 | ERR("Error closing %s apps socket", sock_info->name); |
1ea11eab MD |
674 | } |
675 | sock_info->socket = -1; | |
676 | } | |
46050b1a | 677 | |
9eb62b9c | 678 | /* Register */ |
57773204 | 679 | ret = ustcomm_connect_unix_sock(sock_info->sock_path); |
9eb62b9c | 680 | if (ret < 0) { |
4d3c9523 | 681 | DBG("Info: sessiond not accepting connections to %s apps socket", sock_info->name); |
c0eedf81 | 682 | prev_connect_failed = 1; |
11ff9c7d MD |
683 | /* |
684 | * If we cannot find the sessiond daemon, don't delay | |
685 | * constructor execution. | |
686 | */ | |
edaa1431 | 687 | ret = handle_register_done(sock_info); |
11ff9c7d | 688 | assert(!ret); |
17dfb34b | 689 | ust_unlock(); |
1ea11eab | 690 | goto restart; |
46050b1a MD |
691 | } |
692 | ||
693 | sock_info->socket = sock = ret; | |
694 | ||
695 | /* | |
696 | * Create only one root handle per listener thread for the whole | |
697 | * process lifetime. | |
698 | */ | |
699 | if (sock_info->root_handle == -1) { | |
700 | ret = lttng_abi_create_root_handle(); | |
a51070bb | 701 | if (ret < 0) { |
46050b1a | 702 | ERR("Error creating root handle"); |
17dfb34b | 703 | ust_unlock(); |
46050b1a MD |
704 | goto quit; |
705 | } | |
706 | sock_info->root_handle = ret; | |
9eb62b9c | 707 | } |
1ea11eab | 708 | |
9eb62b9c MD |
709 | ret = register_app_to_sessiond(sock); |
710 | if (ret < 0) { | |
11ff9c7d | 711 | ERR("Error registering to %s apps socket", sock_info->name); |
c0eedf81 | 712 | prev_connect_failed = 1; |
11ff9c7d MD |
713 | /* |
714 | * If we cannot register to the sessiond daemon, don't | |
715 | * delay constructor execution. | |
716 | */ | |
edaa1431 | 717 | ret = handle_register_done(sock_info); |
11ff9c7d | 718 | assert(!ret); |
17dfb34b | 719 | ust_unlock(); |
9eb62b9c MD |
720 | goto restart; |
721 | } | |
17dfb34b | 722 | ust_unlock(); |
46050b1a | 723 | |
d9e99d10 MD |
724 | for (;;) { |
725 | ssize_t len; | |
57773204 | 726 | struct ustcomm_ust_msg lum; |
d9e99d10 | 727 | |
57773204 | 728 | len = ustcomm_recv_unix_sock(sock, &lum, sizeof(lum)); |
d9e99d10 MD |
729 | switch (len) { |
730 | case 0: /* orderly shutdown */ | |
11ff9c7d | 731 | DBG("%s ltt-sessiond has performed an orderly shutdown\n", sock_info->name); |
8236ba10 MD |
732 | ust_lock(); |
733 | /* | |
734 | * Either sessiond has shutdown or refused us by closing the socket. | |
735 | * In either case, we don't want to delay construction execution, | |
736 | * and we need to wait before retry. | |
737 | */ | |
738 | prev_connect_failed = 1; | |
739 | /* | |
740 | * If we cannot register to the sessiond daemon, don't | |
741 | * delay constructor execution. | |
742 | */ | |
743 | ret = handle_register_done(sock_info); | |
744 | assert(!ret); | |
745 | ust_unlock(); | |
d9e99d10 | 746 | goto end; |
e7723462 | 747 | case sizeof(lum): |
d9e99d10 | 748 | DBG("message received\n"); |
11ff9c7d | 749 | ret = handle_message(sock_info, sock, &lum); |
2a80c9d8 | 750 | if (ret < 0) { |
11ff9c7d | 751 | ERR("Error handling message for %s socket", sock_info->name); |
d9e99d10 MD |
752 | } |
753 | continue; | |
754 | case -1: | |
8236ba10 | 755 | DBG("Receive failed from lttng-sessiond with errno %d", errno); |
d9e99d10 | 756 | if (errno == ECONNRESET) { |
11ff9c7d | 757 | ERR("%s remote end closed connection\n", sock_info->name); |
d9e99d10 MD |
758 | goto end; |
759 | } | |
760 | goto end; | |
761 | default: | |
11ff9c7d | 762 | ERR("incorrect message size (%s socket): %zd\n", sock_info->name, len); |
d9e99d10 MD |
763 | continue; |
764 | } | |
765 | ||
766 | } | |
767 | end: | |
9eb62b9c | 768 | goto restart; /* try to reconnect */ |
1ea11eab | 769 | quit: |
d9e99d10 MD |
770 | return NULL; |
771 | } | |
772 | ||
cf12a773 MD |
773 | /* |
774 | * Return values: -1: don't wait. 0: wait forever. 1: timeout wait. | |
775 | */ | |
11ff9c7d MD |
776 | static |
777 | int get_timeout(struct timespec *constructor_timeout) | |
778 | { | |
cf12a773 MD |
779 | long constructor_delay_ms = LTTNG_UST_DEFAULT_CONSTRUCTOR_TIMEOUT_MS; |
780 | char *str_delay; | |
11ff9c7d MD |
781 | int ret; |
782 | ||
69400ac4 | 783 | str_delay = getenv("LTTNG_UST_REGISTER_TIMEOUT"); |
cf12a773 MD |
784 | if (str_delay) { |
785 | constructor_delay_ms = strtol(str_delay, NULL, 10); | |
786 | } | |
787 | ||
788 | switch (constructor_delay_ms) { | |
789 | case -1:/* fall-through */ | |
790 | case 0: | |
791 | return constructor_delay_ms; | |
792 | default: | |
793 | break; | |
794 | } | |
795 | ||
796 | /* | |
797 | * If we are unable to find the current time, don't wait. | |
798 | */ | |
799 | ret = clock_gettime(CLOCK_REALTIME, constructor_timeout); | |
800 | if (ret) { | |
801 | return -1; | |
802 | } | |
95259bd0 MD |
803 | constructor_timeout->tv_sec += constructor_delay_ms / 1000UL; |
804 | constructor_timeout->tv_nsec += | |
805 | (constructor_delay_ms % 1000UL) * 1000000UL; | |
11ff9c7d MD |
806 | if (constructor_timeout->tv_nsec >= 1000000000UL) { |
807 | constructor_timeout->tv_sec++; | |
808 | constructor_timeout->tv_nsec -= 1000000000UL; | |
809 | } | |
cf12a773 | 810 | return 1; |
11ff9c7d | 811 | } |
d9e99d10 | 812 | |
2691221a MD |
813 | /* |
814 | * sessiond monitoring thread: monitor presence of global and per-user | |
815 | * sessiond by polling the application common named pipe. | |
816 | */ | |
817 | /* TODO */ | |
818 | ||
edaa1431 | 819 | void __attribute__((constructor)) lttng_ust_init(void) |
2691221a | 820 | { |
11ff9c7d | 821 | struct timespec constructor_timeout; |
cf12a773 | 822 | int timeout_mode; |
2691221a MD |
823 | int ret; |
824 | ||
edaa1431 MD |
825 | if (uatomic_xchg(&initialized, 1) == 1) |
826 | return; | |
827 | ||
828 | /* | |
829 | * We want precise control over the order in which we construct | |
830 | * our sub-libraries vs starting to receive commands from | |
831 | * sessiond (otherwise leading to errors when trying to create | |
832 | * sessiond before the init functions are completed). | |
833 | */ | |
2691221a | 834 | init_usterr(); |
edaa1431 MD |
835 | init_tracepoint(); |
836 | ltt_ring_buffer_metadata_client_init(); | |
837 | ltt_ring_buffer_client_overwrite_init(); | |
838 | ltt_ring_buffer_client_discard_init(); | |
2691221a | 839 | |
cf12a773 | 840 | timeout_mode = get_timeout(&constructor_timeout); |
11ff9c7d | 841 | |
95259bd0 | 842 | ret = sem_init(&constructor_wait, 0, 0); |
11ff9c7d MD |
843 | assert(!ret); |
844 | ||
8d20bf54 | 845 | ret = setup_local_apps(); |
2691221a | 846 | if (ret) { |
8d20bf54 | 847 | ERR("Error setting up to local apps"); |
2691221a | 848 | } |
1ea11eab MD |
849 | ret = pthread_create(&local_apps.ust_listener, NULL, |
850 | ust_listener_thread, &local_apps); | |
11ff9c7d | 851 | |
8d20bf54 MD |
852 | if (local_apps.allowed) { |
853 | ret = pthread_create(&global_apps.ust_listener, NULL, | |
854 | ust_listener_thread, &global_apps); | |
855 | } else { | |
856 | handle_register_done(&local_apps); | |
857 | } | |
858 | ||
cf12a773 MD |
859 | switch (timeout_mode) { |
860 | case 1: /* timeout wait */ | |
95259bd0 MD |
861 | do { |
862 | ret = sem_timedwait(&constructor_wait, | |
863 | &constructor_timeout); | |
864 | } while (ret < 0 && errno == EINTR); | |
cf12a773 MD |
865 | if (ret < 0 && errno == ETIMEDOUT) { |
866 | ERR("Timed out waiting for ltt-sessiond"); | |
867 | } else { | |
868 | assert(!ret); | |
869 | } | |
870 | break; | |
7b766b16 | 871 | case -1:/* wait forever */ |
95259bd0 MD |
872 | do { |
873 | ret = sem_wait(&constructor_wait); | |
874 | } while (ret < 0 && errno == EINTR); | |
11ff9c7d | 875 | assert(!ret); |
cf12a773 | 876 | break; |
7b766b16 | 877 | case 0: /* no timeout */ |
cf12a773 | 878 | break; |
11ff9c7d | 879 | } |
2691221a MD |
880 | } |
881 | ||
17dfb34b MD |
882 | static |
883 | void lttng_ust_cleanup(int exiting) | |
884 | { | |
efe0de09 | 885 | cleanup_sock_info(&global_apps, exiting); |
17dfb34b | 886 | if (local_apps.allowed) { |
efe0de09 | 887 | cleanup_sock_info(&local_apps, exiting); |
17dfb34b | 888 | } |
efe0de09 MD |
889 | /* |
890 | * The teardown in this function all affect data structures | |
891 | * accessed under the UST lock by the listener thread. This | |
892 | * lock, along with the lttng_ust_comm_should_quit flag, ensure | |
893 | * that none of these threads are accessing this data at this | |
894 | * point. | |
895 | */ | |
17dfb34b | 896 | lttng_ust_abi_exit(); |
003fedf4 | 897 | lttng_ust_events_exit(); |
17dfb34b MD |
898 | ltt_ring_buffer_client_discard_exit(); |
899 | ltt_ring_buffer_client_overwrite_exit(); | |
900 | ltt_ring_buffer_metadata_client_exit(); | |
901 | exit_tracepoint(); | |
902 | if (!exiting) { | |
903 | /* Reinitialize values for fork */ | |
904 | sem_count = 2; | |
905 | lttng_ust_comm_should_quit = 0; | |
906 | initialized = 0; | |
907 | } | |
908 | } | |
909 | ||
edaa1431 | 910 | void __attribute__((destructor)) lttng_ust_exit(void) |
2691221a MD |
911 | { |
912 | int ret; | |
913 | ||
9eb62b9c MD |
914 | /* |
915 | * Using pthread_cancel here because: | |
916 | * A) we don't want to hang application teardown. | |
917 | * B) the thread is not allocating any resource. | |
918 | */ | |
1ea11eab MD |
919 | |
920 | /* | |
921 | * Require the communication thread to quit. Synchronize with | |
922 | * mutexes to ensure it is not in a mutex critical section when | |
923 | * pthread_cancel is later called. | |
924 | */ | |
17dfb34b | 925 | ust_lock(); |
1ea11eab | 926 | lttng_ust_comm_should_quit = 1; |
17dfb34b | 927 | ust_unlock(); |
1ea11eab | 928 | |
f5f94532 | 929 | /* cancel threads */ |
1ea11eab | 930 | ret = pthread_cancel(global_apps.ust_listener); |
9eb62b9c MD |
931 | if (ret) { |
932 | ERR("Error cancelling global ust listener thread"); | |
2691221a | 933 | } |
8d20bf54 MD |
934 | if (local_apps.allowed) { |
935 | ret = pthread_cancel(local_apps.ust_listener); | |
936 | if (ret) { | |
937 | ERR("Error cancelling local ust listener thread"); | |
938 | } | |
8d20bf54 | 939 | } |
efe0de09 MD |
940 | /* |
941 | * Do NOT join threads: use of sys_futex makes it impossible to | |
942 | * join the threads without using async-cancel, but async-cancel | |
943 | * is delivered by a signal, which could hit the target thread | |
944 | * anywhere in its code path, including while the ust_lock() is | |
945 | * held, causing a deadlock for the other thread. Let the OS | |
946 | * cleanup the threads if there are stalled in a syscall. | |
947 | */ | |
17dfb34b | 948 | lttng_ust_cleanup(1); |
2691221a | 949 | } |
e822f505 MD |
950 | |
951 | /* | |
952 | * We exclude the worker threads across fork and clone (except | |
953 | * CLONE_VM), because these system calls only keep the forking thread | |
954 | * running in the child. Therefore, we don't want to call fork or clone | |
955 | * in the middle of an tracepoint or ust tracing state modification. | |
956 | * Holding this mutex protects these structures across fork and clone. | |
957 | */ | |
b728d87e | 958 | void ust_before_fork(sigset_t *save_sigset) |
e822f505 MD |
959 | { |
960 | /* | |
961 | * Disable signals. This is to avoid that the child intervenes | |
962 | * before it is properly setup for tracing. It is safer to | |
963 | * disable all signals, because then we know we are not breaking | |
964 | * anything by restoring the original mask. | |
965 | */ | |
966 | sigset_t all_sigs; | |
967 | int ret; | |
968 | ||
969 | /* Disable signals */ | |
970 | sigfillset(&all_sigs); | |
b728d87e | 971 | ret = sigprocmask(SIG_BLOCK, &all_sigs, save_sigset); |
e822f505 MD |
972 | if (ret == -1) { |
973 | PERROR("sigprocmask"); | |
974 | } | |
17dfb34b | 975 | ust_lock(); |
e822f505 MD |
976 | rcu_bp_before_fork(); |
977 | } | |
978 | ||
b728d87e | 979 | static void ust_after_fork_common(sigset_t *restore_sigset) |
e822f505 MD |
980 | { |
981 | int ret; | |
982 | ||
17dfb34b MD |
983 | DBG("process %d", getpid()); |
984 | ust_unlock(); | |
e822f505 | 985 | /* Restore signals */ |
23c8854a | 986 | ret = sigprocmask(SIG_SETMASK, restore_sigset, NULL); |
e822f505 MD |
987 | if (ret == -1) { |
988 | PERROR("sigprocmask"); | |
989 | } | |
990 | } | |
991 | ||
b728d87e | 992 | void ust_after_fork_parent(sigset_t *restore_sigset) |
e822f505 | 993 | { |
17dfb34b | 994 | DBG("process %d", getpid()); |
e822f505 MD |
995 | rcu_bp_after_fork_parent(); |
996 | /* Release mutexes and reenable signals */ | |
b728d87e | 997 | ust_after_fork_common(restore_sigset); |
e822f505 MD |
998 | } |
999 | ||
17dfb34b MD |
1000 | /* |
1001 | * After fork, in the child, we need to cleanup all the leftover state, | |
1002 | * except the worker thread which already magically disappeared thanks | |
1003 | * to the weird Linux fork semantics. After tyding up, we call | |
1004 | * lttng_ust_init() again to start over as a new PID. | |
1005 | * | |
1006 | * This is meant for forks() that have tracing in the child between the | |
1007 | * fork and following exec call (if there is any). | |
1008 | */ | |
b728d87e | 1009 | void ust_after_fork_child(sigset_t *restore_sigset) |
e822f505 | 1010 | { |
17dfb34b | 1011 | DBG("process %d", getpid()); |
e822f505 MD |
1012 | /* Release urcu mutexes */ |
1013 | rcu_bp_after_fork_child(); | |
17dfb34b | 1014 | lttng_ust_cleanup(0); |
a93bfc45 | 1015 | lttng_context_vtid_reset(); |
e822f505 | 1016 | /* Release mutexes and reenable signals */ |
b728d87e | 1017 | ust_after_fork_common(restore_sigset); |
318dfea9 | 1018 | lttng_ust_init(); |
e822f505 | 1019 | } |